Method of forming a cooling hole in a component

Abstract

There is described a method of forming a cooling hole in a component having a wall comprising a first surface and a second surface, the method comprising: directing a first laser beam onto the first surface of the component wall at an oblique angle so as to drill a first hole extending from the first surface towards the second surface; directing a second laser beam onto the second surface of the component wall at an oblique angle so as to drill a second hole extending from the second surface towards the first surface, the first and second holes intersecting to form a cooling hole passing through the component wall between the first and second surfaces.

We claim: 
     
         1 . A method of forming a cooling hole in a component having a wall comprising a first surface and a second surface, the method comprising:
 directing a first laser beam onto the first surface of the component wall at an oblique angle so as to drill a first hole extending from the first surface towards the second surface; and   directing a second laser beam onto the second surface of the component wall at an oblique angle so as to drill a second hole extending from the second surface towards the first surface, the first and second holes intersecting to form a cooling hole passing through the component wall between the first and second surfaces.   
     
     
         2 . The method as claimed in  claim 1 , wherein the first hole tapers in at least one dimension from the first surface. 
     
     
         3 . The method as claimed in  claim 1 , wherein the second hole tapers in at least one dimension from the second surface. 
     
     
         4 . The method as claimed in  claim 2 , wherein the second hole tapers in at least one dimension from the second surface. 
     
     
         5 . The method as claimed in  claim 4 , wherein the first and second holes taper in dimensions which are perpendicular to one another. 
     
     
         6 . The method as claimed in  claim 5 , wherein, in a direction of flow, the first hole tapers axially such that upstream and downstream walls of the first hole converge thereby forming a laidback entry portion, and the second hole tapers laterally such that side walls of the second hole diverge thereby forming a fanned exit portion. 
     
     
         7 . The method as claimed in  claim 6 , wherein the second hole also tapers axially such that upstream and downstream walls of the second hole converge and such that the fanned exit portion is also laidback. 
     
     
         8 . The method as claimed in  claim 6 , wherein the upstream walls of the first and second holes are axially aligned. 
     
     
         9 . The method as claimed in  claim 1 , wherein the first hole extends through the thickness of the component from the first surface to the second surface. 
     
     
         10 . The method as claimed in  claim 9 , further comprising identifying an exit of the first hole within the second surface and positioning the second laser beam based on the position of the exit of the first hole. 
     
     
         11 . The method as claimed in  claim 1 , wherein the exit of the first hole is identified using a camera. 
     
     
         12 . The method as claimed in  claim 1 , wherein, relative to the component, the first and second laser beams are angled with respect to one another. 
     
     
         13 . The method as claimed in  claim 1 , further comprising ablating with an ablation laser beam a thermal barrier coating from a portion of the first and/or second surface prior to drilling the first and/or second holes. 
     
     
         14 . The method as claimed in  claim 13 , wherein the ablation laser beam is smaller than the first or second laser beam used to drill the first and second holes. 
     
     
         15 . The method as claimed in  claim 1 , wherein the component is a turbine blade, turbine vane or combustion chamber. 
     
     
         16 . A non-transitory computer readable storage medium comprising computer readable instructions which, when executed by a computer, causes performance of a method of forming a cooling hole in a component having a wall comprising a first surface and a second surface, the method comprising:
 directing a first laser beam onto the first surface of the component wall at an oblique angle so as to drill a first hole extending from the first surface towards the second surface; and   directing a second laser beam onto the second surface of the component wall at an oblique angle so as to drill a second hole extending from the second surface towards the first surface, the first and second holes intersecting to form a cooling hole passing through the component wall between the first and second surfaces.   
     
     
         17 . An apparatus for forming a cooling hole in a component having a wall comprising a first surface and a second surface, the apparatus comprising a controller configured to:
 direct a first laser beam onto the first surface of the component wall at an oblique angle so as to drill a first hole extending from the first surface towards the second surface; and   direct a second laser beam onto the second surface of the component wall at an oblique angle so as to drill a second hole extending from the second surface towards the first surface, the first and second holes intersecting to form a cooling hole passing through the component wall between the first and second surfaces.